Exam 4: Principles of Neural and Hormonal Communication

Use the answer code below to answer this section. 1. Two permeability changes that occur at the peak of an action potential increased \_\_\_ 2. Ion movement responsible for the rising decreased and phase of the action potential increased \_\_\_ 3. Ion movement responsible for the falling phase of the action potential influx \_\_\_ 4. Permeability change that occurs at threshold efflux \_\_\_

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Question 1

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$\begin{array}{lr}\text { 1. Two permeability changes that occur at the }\\\text { peak of an action potential }&\text { increased } \mathrm{P}_{\mathrm{Na}+}\_4\_\\\text { 2. Ion movement responsible for the rising }&\text { decreased } \mathrm{P}_{\mathrm{Na+}} \text { and }\\\text { phase of the action potential }&\text { increased } \mathrm{P}_{\mathrm{K}+}\_1\_\\\text { 3. Ion movement responsible for the falling }\\\text { phase of the action potential }&\mathrm{Na} \text { influx }\_2\_\\\text { 4. Permeability change that occurs at threshold }&\mathrm{K}^{+} \text {efflux }\_3\_\end{array}$

Action potentials are initiated at the axon hillock region because it has the lowest threshold voltage.

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Question 2

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True

Complete each of the following statments. During the resting membrane potential, the inside of a neuron has a net ____________________ charge.

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Question 3

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negative

Complete each of the following statments. ____________________ are released into the blood by neurosecretory neurons.

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Question 4

G proteins in the plasma membrane of certain cells may become activated in response to the binding of water-soluble hormones, whereas protein phosphatases are continuously active in these cells.

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Question 5

Complete each of the following statments. cells form myelin around neurons in the PNS, whereas form myelin around neurons in the CNS.

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Question 6

Select the normal direction for the movement of an action potential along part of a neuron.

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Question 7

When a membrane is stimulated due to opening of either chemically-gated Na⁺ or Cl^- channels:

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Question 8

The conduction velocity of a nerve impulse is slower in myelinated fibers than in unmyelinated fibers because myelin acts as an insulator that slows down the flow of current.

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Question 9

If a neuron were experimentally stimulated at both ends simultaneously:

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Question 10

Complete each of the following statments. Opening channels that allow ions or ions result in depolarization of the plasma membrane.

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Question 11

A postsynaptic neuron can either excite or inhibit a presynaptic neuron.

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Question 12

Complete each of the following statments. At ____________________ potential, typically around -55 mv, rapid depolarization occurs.

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Question 13

Use these figures to answer the corresponding questions. The structure labeled "1" is a. part of a chemically-gated channel b. part of a mechanically-gated channel c. the activation gate of a Na+ channel d. part of a chemically-gated channel and the activation gate of a Na+ channel e. none of these

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Question 14

How does a depolarizing graded potential lead to the propagation of action potentials?

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Question 15

The negative charge established along a nerve cell membrane is due to

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Question 16

For the following questions, assume a hypothetical postsynaptic neuron has three presynaptic inputs: neurons X, Y, and Z. Also, assume neuron Z is excitatory. What would you expect at the postsynaptic neuron when neuron Y is stimulated? (Remember that the postsynaptic neuron's membrane potential is decreased by neuron Y.)

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Question 17

Complete each of the following statments. The neuronal relationship where a single presynaptic cell branches to terminate on many other cells is called ____________________.

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Question 18

For the following questions, assume a hypothetical postsynaptic neuron has three presynaptic inputs: neurons X, Y, and Z. Also, assume neuron Z is excitatory. If neurons X and Z receive simultaneous stimulation, what change would you expect in the postsynaptic neuron?

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Question 19

At an inhibitory synapse, the postsynaptic membrane experiences

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Question 20

Exam 4: Principles of Neural and Hormonal Communication

Action potentials are initiated at the axon hillock region because it has the lowest threshold voltage.

Complete each of the following statments. During the resting membrane potential, the inside of a neuron has a net ____________________ charge.

Complete each of the following statments. ____________________ are released into the blood by neurosecretory neurons.

G proteins in the plasma membrane of certain cells may become activated in response to the binding of water-soluble hormones, whereas protein phosphatases are continuously active in these cells.

Complete each of the following statments. ____________________ cells form myelin around neurons in the PNS, whereas ____________________ form myelin around neurons in the CNS.

Select the normal direction for the movement of an action potential along part of a neuron.

When a membrane is stimulated due to opening of either chemically-gated Na+ or Cl- channels:

The conduction velocity of a nerve impulse is slower in myelinated fibers than in unmyelinated fibers because myelin acts as an insulator that slows down the flow of current.

If a neuron were experimentally stimulated at both ends simultaneously:

Complete each of the following statments. Opening channels that allow ____________________ ions or ____________________ ions result in depolarization of the plasma membrane.

A postsynaptic neuron can either excite or inhibit a presynaptic neuron.

Complete each of the following statments. At ____________________ potential, typically around -55 mv, rapid depolarization occurs.

Use these figures to answer the corresponding questions. The structure labeled "1" is a. part of a chemically-gated channel b. part of a mechanically-gated channel c. the activation gate of a Na+ channel d. part of a chemically-gated channel and the activation gate of a Na+ channel e. none of these

How does a depolarizing graded potential lead to the propagation of action potentials?

The negative charge established along a nerve cell membrane is due to

Complete each of the following statments. The neuronal relationship where a single presynaptic cell branches to terminate on many other cells is called ____________________.

For the following questions, assume a hypothetical postsynaptic neuron has three presynaptic inputs: neurons X, Y, and Z. Also, assume neuron Z is excitatory. If neurons X and Z receive simultaneous stimulation, what change would you expect in the postsynaptic neuron?

At an inhibitory synapse, the postsynaptic membrane experiences

Introduction to Physiology and Homeostasis

Cell Physiology

The Plasma Membrane and Membrane Potential

A--The Central Nervous System

B--The Central Nervous System

A--The Peripheral Nervous System: Afferent Division; Special Senses

B--The Peripheral Nervous System: Afferent Division; Special Senses

The Peripheral Nervous System: Efferent Division

A--Muscle Physiology

B--Muscle Physiology

A--Cardiac Physiology

B--Cardiac Physiology

The Blood Vessels and Blood Pressure

The Blood

Body Defenses

A--The Respiratory System

B--The Respiratory System

A--The Urinary System

B--The Urinary System

A--Fluid and Acid-Base Balance

B--Fluid and Acid-Base Balance

A--The Digestive System

B--The Digestive System

Energy Balance and Temperature Regulation

A--Principles of Endocrinology: the Central Endocrine Glands

B--Principles of Endocrinology: the Central Endocrine Glands

A--The Peripheral Endocrine Glands

B--The Peripheral Endocrine Glands

A--The Reproductive System

B--The Reproductive System

Filters

Complete each of the following statments. cells form myelin around neurons in the PNS, whereas form myelin around neurons in the CNS.

When a membrane is stimulated due to opening of either chemically-gated Na⁺ or Cl^- channels:

Complete each of the following statments. Opening channels that allow ions or ions result in depolarization of the plasma membrane.